Ion flow through specific channels controls the generation and conduction of action potentials as well as muscle contraction and transmitter release from nerves. Basic advances in our understanding of channels have usualy come first from nerve membrane because of the technical advantages offered by giant axons. As the tools have been refined and applied to skeletal and cardiac muscle membranes, similar channel properties have usually been observed. Therefore close communication between investigators working on these related cell types is unusually important. This Gordon Conference will offer another opportunity to keep the dialogue vigorous. The entry, movement and binding of calcium ions is of paramount importance in the functoning of most cells. Three sessions will specifically deal with these questions. The recent technical breakthrough called the "patch clamp" is causing an explosion of information about single channel amplitudes and kinetics which will be the focus of one session. An unusual session on new and exciting developments in the study of Acetylcholine channels by molecular biological techniques will point to possible applications to voltage sensitive channels.